In recent years, with respect to magnetic recording media, higher recording densities are being increasingly demanded. Especially these days, in order to achieve further high-density recording, with respect to magnetic heads used in performing reproduction of recorded signals, magnetoresistive magnetic heads (MR heads) are becoming more popular in place of conventional inductive heads, and are being adopted for so-called magnetic tapes and not only hard disks.
As recording media for performing recording and reproduction by such a magnetoresistive magnetic head (MR head), so-called metal thin film type magnetic recording media are used, and in line with the demand for higher density recording described above, achieving a further increase in coercivity and reduction in noise is becoming necessary.
In addition, along with the advances in high density recording, the demand for so-called archivability, where storage over extended periods without the occurrence of degradation in signal quality is possible, is becoming more stringent.
As one that meets such various demands made of magnetic recording media, in Japanese Patent Application Publication No. Hei-11-110731 and Japanese Patent Application Publication No. 2001-250216, there is proposed a magnetic recording medium for use as a hard disk of a configuration in which the magnetic layer is formed of a maghemite thin film containing cobalt.
The magnetic recording medium proposed in each of the publications above, which has a magnetic layer of a ferrite film, has such advantages as being more stable, corrosion resistant and superior in long-term storability as compared to coated type magnetic recording media in which the magnetic layer is formed of a magnetic coating in which magnetic powder is dispersed in a binder, or Co/CoO evaporated magnetic recording media and the like.
However, in applying such a magnetic layer of a ferrite film as described above to magnetic tapes, not only must magnetic properties such as the coercivity Hc of the magnetic layer be improved, but the abrasion of the surface due to contact between an MR head and the magnetic tape becomes a problem, and therefore it becomes important to control the surface properties of the magnetic recording medium.
As such, in the present invention, in view of the problems described above, surface properties of a magnetic tape type magnetic recording medium in particular are studied, and a magnetic recording medium having an appropriate roughness, and in which various properties such as chemical stability, magnetic properties, running stability, running durability are improved, is provided.